"""特征门（T-G5）：单轮/长度/意图黑名单/仓库级信号（纯函数）。

D-G1：t1_hard_ok=False 时禁止判 T1（硬门）；repo_signals=True 时倾向 T3。
"""
from __future__ import annotations

import re
from dataclasses import dataclass
from typing import Any, Dict, List, Optional

from gateway.sense.config import SenseConfig

_REPO_SIGNALS = ("多文件", "仓库", "项目结构", "跨模块", "架构", "脚手架",
                 "migration", "refactor", "scaffold", "repository")


@dataclass
class Features:
    turns: int = 1                    # 非 system 消息数
    est_tokens: int = 0               # 字符/3 估算（中文友好近似）
    single_turn: bool = True
    intent_blocked: bool = False      # 命中意图黑名单
    repo_signals: bool = False        # 仓库级/多文件信号
    over_length: bool = False         # 超出 t1 长度门
    t1_hard_ok: bool = True           # 任一 T1 硬门不过即 False


def _to_text_and_turns(text_or_messages) -> tuple[str, int]:
    if isinstance(text_or_messages, str):
        return text_or_messages, 1
    msgs = [m for m in (text_or_messages or []) if isinstance(m, dict)]
    non_system = [m for m in msgs if str(m.get("role")) != "system"]
    text = "\n".join(str(m.get("content") or "") for m in non_system)
    return text, max(1, len(non_system))


def gate(text_or_messages, consumer: str, cfg: SenseConfig) -> Features:
    """特征门（§7 签名）：返回门特征 + t1_hard_ok。"""
    text, turns = _to_text_and_turns(text_or_messages)
    est_tokens = len(text) // 3
    single_turn = turns <= 1

    blocked = any(word in text for word in cfg.intent_blacklist)
    repo = any(word in text for word in _REPO_SIGNALS)
    over_length = est_tokens > cfg.t1_max_tokens
    multi_turn = turns > cfg.t1_max_turns

    t1_hard_ok = single_turn and not over_length and not blocked and not repo \
        and not multi_turn

    return Features(
        turns=turns, est_tokens=est_tokens, single_turn=single_turn,
        intent_blocked=blocked, repo_signals=repo,
        over_length=over_length, t1_hard_ok=t1_hard_ok)